PubMed Health⌕ Search

Biomedical subjects

K Fukui

Publications and source records attributed to K Fukui.

At least 37 records · Page 2Linked to original sources
PubMed1991

Differential effects of atrial natriuretic peptide and dopamine on urinary protein excretion in chronic glomerulonephritis.

1. To examine whether or not atrial natriuretic peptide-induced proteinuria simply results from increases in urine flow or glomerular filtration rate, we infused dopamine (1 microgram min-1 kg-1) and alpha-human atrial natriuretic peptide (0.025 microgram min-1 kg-1) into nine patients with chronic glomerulonephritis and nine essential hypertensive patients without renal damage, and compared the effects of the two agents on renal function and urinary protein excretion. 2. In patients with chronic glomerulonephritis, dopamine infusion significantly increased urinary sodium excretion (+59%), renal blood flow (+20%) and creatinine clearance (+14%). However, urinary protein excretion was not changed. Addition of atrial natriuretic peptide to the dopamine infusion further increased urinary sodium excretion and maintained creatinine clearance at the same level. In contrast to the infusion of dopamine alone, atrial natriuretic peptide markedly increased urinary protein excretion (77 versus 229 mg min-1 m2, P less than 0.02). Furthermore, the addition of atrial natriuretic peptide elevated the urinary protein/creatinine ratio (1.55 versus 5.35, P less than 0.05), while dopamine alone did not (1.55 versus 1.45, not significant). 3. In essential hypertensive patients, dopamine and dopamine plus ANP showed renal effects similar to those of chronic glomerulonephritis; however, the urinary excretion of protein was not changed significantly. 4. These results suggest that atrial natriuretic peptide may increase urinary protein excretion mainly by increasing the permeability of the damaged glomeruli to protein rather than by simply increasing urine flow or glomerular filtration. Possible mechanisms underlying the proteinuria-increasing effects of atrial natriuretic peptide are discussed.

Adult↗
PubMed1991

Studies on Phe-228 and Leu-307 recombinant mutants of porcine kidney D-amino acid oxidase: expression, purification, and characterization.

Two recombinant mutants of porcine kidney D-amino acid oxidase [EC 1.4.3.3, DAO], in which Tyr(228) and His(307) are replaced with Phe and Leu, respectively, have been expressed in Escherichia coli and purified to apparent homogeneity. The molecular size and amino-terminal sequence of the two mutants were the same as those of the native DAO. Kinetic analysis revealed that the Michaelis constants of the Phe-228 and Leu-307 mutants for D-alanine were 71- and 10-fold and the inhibition constants for benzoate, a potent competitive inhibitor, were 1,189- and 18-fold greater than those of the native DAO, respectively. The maximum velocities of the Phe-228 and Leu-307 mutants were 66 and 58% that of the native DAO. The kinetically estimated dissociation constant of the Leu-307 mutant for FAD was 28-fold greater than that of the native DAO, whereas the value of the Phe-228 mutant was comparable to that of the native DAO. The Leu-307 mutant and the recombinant wild-type DAO were inactivated by D-propargylglycine (D-PG), a suicide substrate. However, the Phe-228 mutant was resistant to the inactivation. Absorption peaks of the Phe-228 mutant were blue-shifted about 10 nm from the corresponding peaks of the wild-type DAO, and the oxidized form was fully reduced by D-alanine without appearance of the purple intermediate.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Purification and characterization of two types of fumarase from Escherichia coli.

Two distinct types of fumarase were purified to homogeneity from aerobically grown Escherichia coli W cells. The amino acid sequences of their NH2-terminals suggest that the two enzymes are the products of the fumA gene (FUMA) and fumC gene (FUMC), respectively. FUMA was separated from FUMC by chromatography on a Q-Sepharose column, and was further purified to homogeneity on Alkyl-Superose, Mono Q, and Superose 12 columns. FUMA is a dimer composed of identical subunits (Mr = 60,000). Although the activity of FUMA rapidly decreased during storage, reactivation was attained by anaerobic incubation with Fe2+ and thiols. Studies on the inactivation and reactivation of FUMA suggested that oxidation and the concomitant release of iron inactivated the enzyme in a reversible manner. While the inactivated FUMA was EPR-detectable, through a signal with g perpendicular = 2.02 and g = 2.00, the active enzyme was EPR-silent. These results suggested FUMA is a member of the 4Fe-4S hydratases represented by aconitase. After the separation of FUMC from FUMA, purification of the former enzyme was accomplished by chromatography on Phenyl-Superose and Matrex Gel Red A columns. FUMC was stable, Fe-independent and quite similar to mammalian fumarases in enzymatic properties.

Amino Acid Sequence↗
PubMed1991

Genetic and molecular properties of human and rat renin-binding proteins with reference to the function of the leucine zipper motif.

The presence of a leucine zipper motif was recognized in the deduced amino acid sequences of human and rat renin-binding proteins (RnBPs) on cloning and sequence analysis of the RnBP cDNAs. The in vitro synthesized RnBPs, with the respective cDNAs, formed heterodimers with porcine renin and homodimers. On comparison of these properties with those of porcine RnBP, the leucine zipper motif was suggested to be a functional domain common to animal RnBPs. In addition to the motif, a hydrophobic domain adjacent to the motif and 10 cysteine residues were also well conserved in the three RnBPs. Moreover, about 85% of their amino acid sequences were identical. The RnBP mRNAs were expressed in the kidneys as the same size of 1.5-kb and the genes are suggested to exist as single copies in the genomes. Despite the high similarities in genetic and molecular properties, the molecular weights of human and rat RnBPs were 43,000, which is 1,000 larger than that of porcine RnBP. The immunoreactivities of human and rat RnBPs toward anti-porcine RnBP antiserum were 88 and 8% that of porcine RnBP, respectively, and the affinities of the two RnBPs for porcine renin were remarkably less than that of porcine RnBP. Moreover, the human and rat RnBP homodimers were partly dissociated under the conditions under which porcine RnBP existed as a dimer. These results indicate distinct differences in the molecular properties among the three RnBPs, in spite of their being highly similar structurally and functionally.

Amino Acid Sequence↗
PubMed1991

Effects of cromakalim on renal hemodynamics and function in dogs: comparison with nicardipine.

The effects of cromakalin, a potassium channel opener, on renal hemodynamics and renal function were investigated in pentobarbital-anesthetized dogs. Intrarenal infusion of cromakalim at 0.5 micrograms/kg/min resulted in significant increases in renal blood flow (RBF), glomerular filtration rate (GFR), urine flow, and renin release. The urinary excretion rate of sodium increased by the same proportion as that of calcium. Free water reabsorption rate/osmolar clearance did not significantly change throughout the experiments. These data suggest that cromakalim did not inhibit sodium transport at the medullary portion of the ascending limb of Henle's loop and may have increased the delivery of sodium to Henle's loop. Intrarenal infusion of nicardipine increased RBF, GFR, urine flow, and the urinary excretion of electrolytes (Na, K, and Ca). The renal effects of cromakalim were very similar to those of nicardipine. Cromakalim was superimposed on a nicardipine infusion of a maximal effective dose. Superimposition of cromakalim to the nicardipine infusion did not cause any additional changes in renal hemodynamics and renal function. These data suggest that cromakalim and nicardipine exert their effects on renal hemodynamics and function via the same pathway.

Animals↗
PubMed1991

Aspartate and asparagine as electron acceptors for Wolinella recta.

Since fumarate and nitrate are not usually available in the oral ecosystem, it was investigated whether aspartate and asparagine could be used as alternative electron acceptors by Wolinella recta, which is strictly dependent on a respiratory metabolism with formate or H2 as electron donors. Both aspartate and asparagine were indeed shown to support growth of W. recta with formate as electron donor. Fermentative growth with aspartate alone was not possible. Succinate was the major end-product and was formed in equimolar quantities with respect to the amount of formate consumed. The consumption of aspartate and asparagine, on a molar basis, was 10-30% higher than that of formate. Cell-free extracts were prepared from cells grown with formate + fumarate, formate + aspartate, formate + asparagine, and formate + fumarate + aspartate. All these extracts contained high activities of asparaginase, aspartate ammonia-lyase and fumarate-reductase, but no significant activity of aspartate aminotransferase was detected, indicating that fumarate was synthesized directly from aspartate and subsequently reduced to succinate. Based on these results it seems likely that aspartate and asparagine can serve as natural electron acceptors for W. recta in periodontal lesions in which proteolytic bacteria abound.

Asparaginase↗
PubMed1991

Atrial natriuretic peptide inhibits the aldosterone response to metoclopramide in patients with glomerular disease and essential hypertension.

1. We examined the effects of metoclopramide (MCP: 10 mg i.v.) on plasma atrial natriuretic peptide (ANP) and aldosterone concentrations (PAC) and the effect of ANP on MCP-induced PAC in four patients with primary glomerular diseases and seven patients with essential hypertension. 2. MCP injection caused no significant changes in plasma ANP. MCP produced a marked increase in PAC without a significant change in plasma renin activity. 3. The increase in PAC induced by MCP injection was markedly attenuated when preceded by the infusion of ANP (25 ng/kg per min). 4. These results suggest that the dopaminergic D2 mechanism is not involved in the regulation of ANP secretion and that ANP modulates the dopaminergic regulation of aldosterone secretion.

Adult↗
PubMed1991

Nuclease-sensitive binding of an Actinobacillus actinomycetemcomitans leukotoxin to the bacterial cell surface.

A leukotoxin of Actinobacillus actinomycetemcomitans 301-b was solubilized from cell-associated membrane vesicles by treatment with externally added DNase and RNase and was further purified by a procedure which included ammonium sulfate fractionation, gel filtration chromatography, and ion-exchange chromatography. The purified toxin had a molecular mass of 113,000 Da by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and a high isoelectric point (approximately 8.8). From these characteristics, it was to be expected that the membrane vesicle toxin was almost identical to the leukotoxin extracted with polymyxin B in an earlier study (C.-C. Tsai, B. J. Shenker, J. M. DiRienzo, D. Malamud, and N. S. Taichman, Infect, Immun. 43:700-705, 1984). The treatment with DNase and RNase was also highly effective for solubilizing the leukotoxin directly from whole cells, suggesting that the toxin is secreted extracellularly but retained in nucleic acids on the outermost surface of bacterial cells.

Aggregatibacter actinomycetemcomitans↗
PubMed1991

Peptide sequences for sucrose splitting and glucan binding within Streptococcus sobrinus glucosyltransferase (water-insoluble glucan synthetase).

The gene encoding glucosyltransferase responsible for water-insoluble glucan synthesis (GTF-I) of Streptococcus sobrinus (formerly Streptococcus mutans 6715) was cloned, expressed, and sequenced. A gene bank from S. sobrinus 6715 DNA was constructed in vector pUC18 and screened with anti-GTF-I antibody to detect clones producing GTF-I peptide. Five immunopositive clones were isolated, all of which produced peptides that bound alpha-1,6 glucan. GTF-I activity was found in only two large peptides: one stretching over the full length of the GTF-I peptide and composed of about 1,600 amino acid residues (AB1 clone) and the other lacking about 80 N-terminal residues and about 260 C-terminal residues (AB2 clone). A deletion study of the AB2 clone indicated that specific glucan binding, which is essential for water-insoluble glucan synthesis, was lost prior to sucrase activity with an increase in deletion from the 3' end of the GTF-I gene. These results suggest that the GTF-I peptide consists of three segments: that for sucrose splitting (approximately 1,100 residues), that for glucan binding (approximately 240 residues), and that of unknown function (approximately 260 residues), in order from the N terminus. The primary structure of the GTF-I peptide, deduced by DNA sequencing of the AB1 clone, was found to be very similar to that of the homologous protein from another strain of S. sobrinus.

Amino Acid Sequence↗
PubMed1991

Effects of atrial natriuretic peptide on urinary protein excretion in mesangial proliferative glomerulonephritis.

Atrial natriuretic peptide (ANP) increases proteinuria in primary glomerular disease. To study whether mesangial proliferation influences this effect, we infused alpha-human ANP at 25 ng/kg/min for 40 min into 6 patients with minor glomerular abnormalities (MGA), 10 with focal glomerulonephritis (FGN) and 8 with diffuse glomerulonephritis (DGN), and determined its renal effects. ANP significantly increased urinary excretions of Na and protein in all groups. Increases in urinary Na excretion were comparable among the groups (about + 200%), while increases in urinary protein excretion were greater in DGN than in the other two groups (DGN + 153 micrograms/min/1.73 m2, MGA + 77 micrograms/min/1.73 m2, FGN + 70 micrograms/min/1.73 m2). This increase was not related to the preinfusion level of proteinuria. Furthermore, the ratio of urinary protein to creatinine was significantly elevated by about 250% in the three groups. Thus, ANP seems to increase the permeability of the glomerular basement membrane to protein, particularly in patients with DGN, possibly through mesangial proliferation and the associated changes in adjacent tissues.

Adolescent↗
PubMed1991

Effects of prolonged treatment with beta-adrenoceptor antagonist, carteolol on systemic and regional hemodynamics in stroke-prone spontaneously hypertensive rats.

The present study was designed to determine the regional hemodynamic effects of prolonged beta-adrenergic receptor inhibition in conscious stroke-prone spontaneously hypertensive rats (SHRSP) using a radioactive microsphere method. When the regional blood flow was compared between 10 and 30 weeks of age, the age-related changes in organ blood flow were observed in several organs, i.e., the reduction of flow rate in kidney, adrenal gland and intestines. The reduction of flow rate in these organs contributes strongly to the age-related rise of total peripheral resistance. Carteolol, a beta-adrenoceptor antagonist, was given at a dose of 10 mg/kg/d from 10 to 30 weeks of age. These animals gained more weight than the untreated control SHRSPs, and heart rate was reduced significantly. Blood pressure was not affected. However, the prolonged treatment with carteolol prevented the age-related reduction of the blood flow rate in the kidney, adrenal gland and intestines. Thus, our findings indicate that carteolol had appreciable and beneficial effects on the maintenance of flow rates in the above organs of SHRSP without any change in blood pressure.

Animals↗
PubMed1991

Effects of water deprivation and morphine administration on atrial natriuretic peptide mRNA levels in rat auricles.

We investigated the influences of two potent stimuli, water deprivation (5 days) and morphine administration (100 mg/kg), on the level of atrial natriuretic peptide (ANP) mRNA in the rat auricles. The ANP mRNA level was measured by Northern blot hybridization analysis. The plasma concentration of ANP decreased in water deprived rats, and the ANP mRNA levels in both auricles of these rats were lower than those of the control, particularly in the left auricle. Thirty minutes after the injection of morphine, the plasma concentration of ANP markedly increased, while morphine increased the right auricular ANP mRNA level 4 hr after the administration. These data suggest that these stimuli can change ANP gene expression in the auricles and that the changes are induced differentially in both auricles.

Animals↗
PubMed1991

[Individual identification from extremely contaminated forensic specimens by sequencing cloned mitochondrial D-loop genes].

The PCR-amplified fragments of the human mitochondrial DNA were cloned, and independent clones were sequenced to identify individuals from trace amount of a composite forensic specimen originated from plural number of the individuals. The amplification of the mitochondrial DNA is suitable for forensic analysis where the specimens are highly degraded in most cases for its extremely high copy number and polymorphism as compared with the chromosomal DNA. And cloning procedure simplifies to correspond results to each individuals. Except three non-related individuals out of 34 cases analysed so far who gave identical sequence, the sequence in this segment were highly specific to each individuals and this procedure was extremely beneficial in individual identification from trace amount of highly contaminated and degraded forensic specimens.

Base Sequence↗
PubMed1991

[Effect of recombinant human erythropoietin on autologous blood pre-donation in open heart surgery].

We have used recombinant human erythropoietin (EPO) with an autologous blood predonation in open heart surgery looking forward to preventing patient's blood level of hemoglobin and quick recovery in post-operative period. In our results, patient's value of hemoglobin (Hb) and hematocrit (Ht) decreased due to autologous blood predonation. In group A (autologous blood predonation with EPO administration), however, predonated blood volume were larger than in group B (without EPO administration), decreased value of Hb and Ht were smaller than in group B. The counts of reticulocyte were higher in group A at the operative day. Among six cases phlebotomized with EPO administration, five cases required no homologous blood transfusion for their hospital course. Postoperative recovery of patient's Ht value were earlier in preoperative blood donation group. In particular, patients who administered EPO intravenously have showed fair recovery from anemia. EPO is very effective drug to prevent patients from the developing anemia as a complication of autologous blood predonation. We conclude that autologous blood predonation with EPO administration is beneficial method to reduce homologous blood requirement in open heart surgery.

Adolescent↗
PubMed1991

Differential diagnosis of gastric adenoma and type IIa early gastric cancer.

The endoscopic and radiographic findings of 45 gastric adenomas in 39 patients were followed for 6 months to 13 years and compared with type IIa early gastric cancer observed in 9 patients. Difficulties in the differential diagnosis of these disorders were evaluated. The following features were suggestive of gastric adenomas: clustered lesion; protuberance with gentle slope; smooth surface; and relatively young patients. Discrimination of adenoma from type IIa early gastric cancer is often difficult by visual observation alone; biopsy was essential in most patients. A group III adenoma verified on biopsy should be followed closely because the lesion may harbor a cancer (so-called carcinoma-in-adenoma) or a cancer may later develop.

Adenoma↗